A popularly employed method for controlling an electric power system is centralized control of an electric power system (for example, see Patent Document 1). Centralized control of an electric power system requires building of a mechanism for concentrating information and a large-scale control system for grasping and analyzing the whole system configuration condition and also optimizing the whole system. Such a system is easily applied in countries and regions where electric power supply infrastructure has developed to some extent, because it can be built additionally. However, in regions including emerging countries where electric power infrastructure has not developed, new building of the above system requires a large investment in development of the infrastructure.
On the other hand, in terms of optimization of the whole system, there is a proposed approach of distributed control, which is less efficient but enables electric power control without a large investment by regulating voltages between neighboring power plants or comparatively near power plants (for example, see Patent Document 2). In control of an electric power system, generally, matrix calculation is carried out on the basis of information of each generator, and a solution is found. In the case of concentrated control mentioned above, large-scale matrix calculation should be done because all the information is included. On the other hand, in the case of distributed control, sparse matrix calculation is done because control between neighboring or near power plants is executed, and therefore, the amount of calculation is considerably less.
Patent Document 1: Japanese Unexamined Patent Application Publication No. JP-A 2002-165367
Patent Document 2: Japanese Unexamined Patent Application Publication No. JP-A 2010-057311
In recent years, in consideration of the protection of global environment and energy security, natural energy such as solar light, biomass and wind power has been introduced worldwide. However, such natural energy has a problem with the stability of supply and, as such power sources become more popular in the future, it will become a critical issue how to keep the stability of the whole electric power network. In other words, when it comes to electric power generation by natural energy, new entrants to electric power supply increase because the introduction cost is low though the power generation capacity of each generator is small, and moreover, it is worried about that enough reserves cannot be secured in a small-scale electric power system configured mostly by such generators.